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I have just created a large set of new quizzes designed to test your skills at estimating numbers. You can enter the site at SibleyBirds.com, and you will also find a brief discussion of the art of estimating numbers. This is very much a “beta” version, so thanks in advance for your patience if anything doesn’t […]

No matter how serious you are about birding, or how much you want to see hawks, a Mourning Dove will always have a stronger interest in spotting them. Birds that are in mortal danger of hawk attacks have excellent eyesight and are constantly alert to any potential threat. It’s a safe bet that they will spot […]

Clicking on any image will open the full size image in a new window, so you can study the larger size and then return to the quiz – still in progress – in this window. Thanks to Martin Reid for allowing the use of his photos (and for counting the birds in each one!).

Find the Greater Secondary Coverts These are some of my digiscoped photos from a recent trip to Belize, all taken at the fantastic Black Rock Lodge. On each photo body parts are labeled with letters, and your challenge is to identify the greater secondary coverts on each bird. Good luck!

By the end of February, even in cold and snowy Massachusetts, Red-tailed Hawks are courting and forming pairs in preparation for nesting. It’s common to see the male and female of a pair sitting close to each other in a tree, and this provides a very powerful clue to identification. Hawks are generally solitary and […]

One of the biggest challenges of identifying a Cackling Goose is just finding one, especially in the east where the species is rare and occurs mostly as single birds (of the relatively large and pale Richardson’s subspecies) among big flocks of Canadas. The photos below show one Richardson’s Cackling Goose among Canadas. See if you […]

Most Passerines only hold juvenal plumage for a few weeks, quickly molting to a more adult-like plumage soon after they fledge and before fall migration. It’s a plumage that is seen almost entirely on the breeding grounds, but the breeding grounds (and fledging time) of many birds overlaps broadly with the fall migration of others, […]